Agriculture Reference
In-Depth Information
23.1 INTRODUCTION
Biological potential of a field depends totally on the variety of genetic system, which
is manifested by the degree of effective use of ecological potential, which is created
by humans with technical equipments; hence, rentable technical and soil-reclamation
operations depend on it.
Vavilov [1] defi ned breeding as an evolution directed by human power. Breeding is
based on the selection of plants with the changes caused by changes in their genotype.
Understanding of the variability is of fundamental importance in studying the base-
line, which is the most important part of breeding.
Wide use of modern methods of studying genetic effect enables us to penetrate
into the most important processes, which make the base of heredity, to discover its
regularity, as well as to solve one of the main tasks of breeding—creating the genetic
diversity of baseline [2].
Gene and chromosome mutations are the main source of all heredity variabilities
and the materials for evolution and breeding [3]. According to the law of homologous
series proposed by M.I. Vavilov, the world collection of breeders can be reproduced
by means of mutation [4].
Mutations are heredity change, making genetic base of variability and the raw
material for selection. As Vavilov affi rms [5], mutations are signifi cant in winter wheat
forms created by natural and artifi cial hybridization.
Mutation variability underlies any baseline for breeding, as the initial primary
changeability arises only as a result of mutation. Breeding and artifi cial selection
are based on the processes of spontaneous changeability of genes and chromosomes.
Spontaneous mutational changeability is important in evolution of an organic world,
although it arises with low frequency [6-8].
Primitive breeding, based on the selection of spontaneous mutations and hybrids
for thousands of years, have created valuable forms of crops hard to be improved, even
with the use of modern breeding methods.
Mutations are displayed in changes of plant organs (root, steam, leaf, infl ores-
cence, fl ower, fruit, and seeds) and their study gives rich material for taxonomy. Ex-
perimental mutagenesis use enables to disclose all the possibilities of species in forms
on the basis of received polymorphism and to create rich collections of genetically
diversity of some plants species on the basis of the received mutations.
Mutation process is a “supplier” of new elementary material; it supports genetic
heterogeneity of natural populations. However, plant breeding could not be based on
using only spontaneous mutations as their frequency is quite low. The induced mu-
tagenesis is a powerful method of solving multiple theoretical and practical tasks of
genetics and breeding.
Methods of induced mutagenesis complement all the other parts of initial mate-
rial studied, as they enable to involve the variegated material in the form of gene and
chromosome mutations into the breeding, although the mutations are just a baseline as
they can give rise to new varieties only after they have undergone strict selection, in
some cases even with hybridization [9].
 
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